Telephone supervisory system.



W. S. PAGA.

' TELEPHONE SUPERVISORY SYSTEM.

'APPLIO ATION TILED H0113, 1908.

933,335, v- Patented sepn. y, 1909.

' lhllllla 7 and secondary winding 8.

signal circuit includes secondary winding 8,-

calling and station B as about to be called. able to omit the audiblerelation between the The cord pair at G is of a type having four relaysper cord air. The cords are separated conductive y by condensers 1 and2.

5 On the answeringcord supervisory relays 3 and 4 are energized bycurrent flowing through the substation bridge and through the cut-offrelay 5; relay 3 closes the circuit of lamp 6 and relay 4 opens thecircuit of 1c lamp 6. Upon cessation of current through the substationbridge at A, relay 4 will release its armature and close the circuit oflam 6. In series with lam 6 I introduce the induction coil having primarwindings n audible conductors 9 and operators receiving telephone 10.

.It is obvious that when the circuit of lamp 2o 6, containing alsobattery X and induction coil winding 7,'is either closed or opened byrelay 3 or 4, the starting or stopping of current in winding 7 willcause'an inductive pulsation in secondary winding 8; the relation of thewindings 7 and 8, the conductors 9, and the receiving telephone 10 shallbe such that the resultant current through the receiver 10 shall producean audible but not objectionably loud click. It is obvious thereforethat the working of the switchhook up and down at substation A' and thusbreaking and making repeatedly the contact of the hook switch will,:bycontrolling relay 4' thus controlling the circuit of lamp 6 and primarywinding 7, produce a series of clicks in the o rators t ephone 1Ocharactei'istically' ,di erent from the isolated and intermittent clickscaused by the regular acts of subscribers in answering calls and in 40hanging .up receivers permanently for disconnection. Induction coilhaving winding 7 8{ 1s related'to the other. plug of the cord pair inthe same manner, and transmits to I the telephone 10 audible signalsfrom the station'B. As m'a-ny as desired of the operators lugs may beconnected by an inductive llnk to the operators receiving telephone. Thediagram of the figure accompanying contemplates that all of her plugsand supervisory lamps shall be so connected;

the secondaries 8 8 etc. of the induction coils may rouped in andesiredmanner, series, multlp e, or multip e are, in association withthe conductors 9 which lead to the telephone 10.

In large exchanges, particularly in exchanges where trunking isused'extensively and in exchanges wheremeasured rates are .used, it iscustomary to have an operator igmore a signal for attention from herringing plug, the action of an operator upon such a signal being merelyto disconnect the plugs, thus permitting the signalingsubscriber to callin upon his proper A-operator. Under such operating rules it may bedeemed advisringing plug and the' operators receiving telephone; thiswill reduce the total number of clicks to be received by the operator,yet leave her easily attracted to the flashing of a lamp by one of herown subscribers connected upon any answering plug. I call at tention tothe fact, however, that the operators attention should be attracted forprompt disconnection of her ringing plug so that the subscribersignaling her may be enabled to signal his own operator more promptly.

The induction coils used may be of any desired characteristics,depending upon the strength preferred for the click in the operatorsreceiver and depending upon the mode of connecting the secondariesbefore attaching to the circuit wires 9. I have found that withconnections shown in the figure resistance for the winding 7 of .25 to.5 ohms and for thewinding 8 of 200 ohms give very satisfactory results.Itis found by experience also that the circuit is useful in warning anoperator of the fact that some other operator may have plugged in andrung on a line that vthe first operator may have'had connected, as theact of the second operator plugging in and ringing on a busy line willcause the cord relay of the first connected cordto be chattered orrattled, and will thereby cause an interrupted current to flow throughthe primary of one of the induction coils, thus giving a' very decidedsignal in the operators receiving telephone who may have had theoriginal connection.

The desideratum in the system of my invention is that a signaling linkbe provided at -all times between the supervisory circuits associatedwith the operators keyboard equi ment and the operators telephone. It iso .vious that many forms of combinin the ele ments to produce the resultare possible, and also that divers elements may be combined to the sameresult. Combinations of condensers or impedances or both may replace theinduction coils whose windings are 7 and 8. Also the windin 7, insteadof being individual to a single amp, may be common to both lamps of apair or may be common to all the lamps of the operators equipment, therebeing but a single such windin per operator and that winding being incluin v the lamp signal bus wire of her position.

In this case, a click in the receiver will be heard for each change incurrent value, the

current increasing or decreasing slightly as any lamp is lighted orextinguished; the characteristics and limitations of existingsupervisory circuits in an exchange where it is desired to install myinvention to supplement an existing supervisory system, may in someinstances be such as to render this method the most desirable.

In the system of my invention, the subscribers hook is enabled tooperate as a telegraph key to produce. audible telegraphic signals inthe operators tele hone receiver. This interpretation of the guredescribes the relayet as the telegraph line-relay, the 5 receiver 10 inconjunction with the repeat- 1 ing coil 78 forming an audibletelegraphic tors receiving telephone; and an induction coil having itsprimary winding included in said cn-cuit and its secondary windingconnected to said telephone, substantially as described.

2.111 a telephone system, a subscribers line; a relay controlled oversaid line; a local circuit controlled by said relay; an operatorsreceiving telephone; andan inductive link connecting said circuit andsaid telephone, substantially-as described.

3. In a telephone system, a subscribers line; a relay controlled at alltimes over said line; a local circuit controlled by said relay; anoperators receiving telephone; and means for producing at any time anaudiblesignal in said telephone when said relay is operated,substantially as described.

. 4. In a telephone systemfa;circuitadapted' to be opened and closed andadapted to be so controlled by a subscribers hookswitch;

' an operate'rs receiving telephone; and means operative at all timesfor producing a current. through said telgphone when saidcircuit isopened or clos soriloed. r I

5. In a telephone system, a circuit adapted to beopened and closed and;adapted to be so controlled by a subscribers hookswitch; an operatorsreceiving telephone; andmeans operative at all times for producing aclicking sound in said'telephone when said cirsubstantially as'decuit isso controlled, substantially as described. I 6. In a telephone system, avisual superan operators receiving telephone; and an induction coilhaving its prlmary Winding included in said circuit and its secondarywinding connected to saidtelephone, substantially as described.

8. In a telephone'system, a visual su ervisory signal; a controllingcircuit there or; an operators receiving'telephone; and means .forproducing an audible signal-in said telephone at all times uponenergization or deenergization of said signal, substantially asdescribed.

- 9. In a telephone system, a visual 'su ervisory signal; a controllingcircuit there or; an operators receiving telephone; and means operativeat all times for producing an audlble signal in said telephone upon the.breaking of said circuit, substantially as described.

10. In a telephone system, a telegraph circuit extending from anoperators connecting apparatus to a substation, said circuit beingoperative at all times during the connection otthe o' erators conectin'gappara-, tus with the sai station, and producing an audible signal inthe operators telephone in response to current changes in the saidcircuit, substantiall as described.

' 1 1. In a tele one system, a supervisory relay; a visua signalcontrolled thereby; and an auxiliary su ervisory signal circuitcontrolled exclusive y by said relay at all times duringthe continuanceof connection I and including the operators receiver as an audiblesignal device;

Signed by me at Oil City, county of Venango and State of Pennsylvania,in the presence of two witnesses.

WILLIAM s. PAC'A.

Witnesses:

J S. MASON, T. P. CADIGAN.

